Update clang, llvm, lld, lldb, compiler-rt and libc++ to 4.0.0 release:

MFC r309142 (by emaste):

Add WITH_LLD_AS_LD build knob

If set it installs LLD as /usr/bin/ld.  LLD (as of version 3.9) is not
capable of linking the world and kernel, but can self-host and link many
substantial applications. GNU ld continues to be used for the world and
kernel build, regardless of how this knob is set.

It is on by default for arm64, and off for all other CPU architectures.

Sponsored by:	The FreeBSD Foundation

MFC r310840:

Reapply 310775, now it also builds correctly if lldb is disabled:

Move llvm-objdump from CLANG_EXTRAS to installed by default

We currently install three tools from binutils 2.17.50: as, ld, and
objdump. Work is underway to migrate to a permissively-licensed
tool-chain, with one goal being the retirement of binutils 2.17.50.

LLVM's llvm-objdump is intended to be compatible with GNU objdump
although it is currently missing some options and may have formatting
differences. Enable it by default for testing and further investigation.
It may later be changed to install as /usr/bin/objdump, it becomes a
fully viable replacement.

Reviewed by:	emaste
Differential Revision:	https://reviews.freebsd.org/D8879

MFC r312855 (by emaste):

Rename LLD_AS_LD to LLD_IS_LD, for consistency with CLANG_IS_CC

Reported by:	Dan McGregor <dan.mcgregor usask.ca>

MFC r313559 | glebius | 2017-02-10 18:34:48 +0100 (Fri, 10 Feb 2017) | 5 lines

Don't check struct rtentry on FreeBSD, it is an internal kernel structure.
On other systems it may be API structure for SIOCADDRT/SIOCDELRT.

Reviewed by:	emaste, dim

MFC r314152 (by jkim):

Remove an assembler flag, which is redundant since r309124.  The upstream
took care of it by introducing a macro NO_EXEC_STACK_DIRECTIVE.

http://llvm.org/viewvc/llvm-project?rev=273500&view=rev

Reviewed by:	dim

MFC r314564:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
4.0.0 (branches/release_40 296509).  The release will follow soon.

Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
support to build; see UPDATING for more information.

Also note that as of 4.0.0, lld should be able to link the base system
on amd64 and aarch64.  See the WITH_LLD_IS_LLD setting in src.conf(5).
Though please be aware that this is work in progress.

Release notes for llvm, clang and lld will be available here:
<http://releases.llvm.org/4.0.0/docs/ReleaseNotes.html>
<http://releases.llvm.org/4.0.0/tools/clang/docs/ReleaseNotes.html>
<http://releases.llvm.org/4.0.0/tools/lld/docs/ReleaseNotes.html>

Thanks to Ed Maste, Jan Beich, Antoine Brodin and Eric Fiselier for
their help.

Relnotes:	yes
Exp-run:	antoine
PR:		215969, 216008

MFC r314708:

For now, revert r287232 from upstream llvm trunk (by Daniil Fukalov):

  [SCEV] limit recursion depth of CompareSCEVComplexity

  Summary:
  CompareSCEVComplexity goes too deep (50+ on a quite a big unrolled
  loop) and runs almost infinite time.

  Added cache of "equal" SCEV pairs to earlier cutoff of further
  estimation. Recursion depth limit was also introduced as a parameter.

  Reviewers: sanjoy

  Subscribers: mzolotukhin, tstellarAMD, llvm-commits

  Differential Revision: https://reviews.llvm.org/D26389

This commit is the cause of excessive compile times on skein_block.c
(and possibly other files) during kernel builds on amd64.

We never saw the problematic behavior described in this upstream commit,
so for now it is better to revert it.  An upstream bug has been filed
here: https://bugs.llvm.org/show_bug.cgi?id=32142

Reported by:	mjg

MFC r314795:

Reapply r287232 from upstream llvm trunk (by Daniil Fukalov):

  [SCEV] limit recursion depth of CompareSCEVComplexity

  Summary:
  CompareSCEVComplexity goes too deep (50+ on a quite a big unrolled
  loop) and runs almost infinite time.

  Added cache of "equal" SCEV pairs to earlier cutoff of further
  estimation. Recursion depth limit was also introduced as a parameter.

  Reviewers: sanjoy

  Subscribers: mzolotukhin, tstellarAMD, llvm-commits

  Differential Revision: https://reviews.llvm.org/D26389

Pull in r296992 from upstream llvm trunk (by Sanjoy Das):

  [SCEV] Decrease the recursion threshold for CompareValueComplexity

  Fixes PR32142.

  r287232 accidentally increased the recursion threshold for
  CompareValueComplexity from 2 to 32.  This change reverses that
  change by introducing a separate flag for CompareValueComplexity's
  threshold.

The latter revision fixes the excessive compile times for skein_block.c.

MFC r314907 | mmel | 2017-03-08 12:40:27 +0100 (Wed, 08 Mar 2017) | 7 lines

Unbreak ARMv6 world.

The new compiler_rt library imported with clang 4.0.0 have several fatal
issues (non-functional __udivsi3 for example) with ARM specific instrict
functions. As temporary workaround, until upstream solve these problems,
disable all thumb[1][2] related feature.

MFC r315016:

Update clang, llvm, lld, lldb, compiler-rt and libc++ to 4.0.0 release.
We were already very close to the last release candidate, so this is a
pretty minor update.

Relnotes:	yes

MFC r316005:

Revert r314907, and pull in r298713 from upstream compiler-rt trunk (by
Weiming Zhao):

  builtins: Select correct code fragments when compiling for Thumb1/Thum2/ARM ISA.

  Summary:
  Value of __ARM_ARCH_ISA_THUMB isn't based on the actual compilation
  mode (-mthumb, -marm), it reflect's capability of given CPU.

  Due to this:
   - use  __tbumb__ and __thumb2__ insteand of __ARM_ARCH_ISA_THUMB
   - use '.thumb' directive consistently  in all affected files
   - decorate all thumb functions using
     DEFINE_COMPILERRT_THUMB_FUNCTION()

  ---------
  Note: This patch doesn't fix broken Thumb1 variant of __udivsi3 !

  Reviewers: weimingz, rengolin, compnerd

  Subscribers: aemerson, dim

  Differential Revision: https://reviews.llvm.org/D30938

Discussed with:	mmel

1 files changed, 224 insertions, 314 deletions

diff --git a/contrib/llvm/tools/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.h b/contrib/llvm/tools/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.h
index 2a01bce..1f3fa17 100644
--- a/contrib/llvm/tools/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.h
+++ b/contrib/llvm/tools/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.h
@@ -12,365 +12,275 @@
 
 // C Includes
 // C++ Includes
-#include <string>
+#include <condition_variable>
+#include <mutex>
 #include <queue>
+#include <string>
 #include <vector>
 
 // Other libraries and framework includes
 // Project includes
-#include "lldb/lldb-public.h"
 #include "lldb/Core/Communication.h"
 #include "lldb/Core/Listener.h"
 #include "lldb/Host/HostThread.h"
-#include "lldb/Host/Mutex.h"
 #include "lldb/Host/Predicate.h"
-#include "lldb/Host/TimeValue.h"
 #include "lldb/Interpreter/Args.h"
+#include "lldb/lldb-public.h"
 
 #include "Utility/StringExtractorGDBRemote.h"
 
 namespace lldb_private {
 namespace process_gdb_remote {
 
-typedef enum
-{
-    eStoppointInvalid = -1,
-    eBreakpointSoftware = 0,
-    eBreakpointHardware,
-    eWatchpointWrite,
-    eWatchpointRead,
-    eWatchpointReadWrite
+typedef enum {
+  eStoppointInvalid = -1,
+  eBreakpointSoftware = 0,
+  eBreakpointHardware,
+  eWatchpointWrite,
+  eWatchpointRead,
+  eWatchpointReadWrite
 } GDBStoppointType;
 
-enum class CompressionType
-{
-    None = 0,       // no compression
-    ZlibDeflate,    // zlib's deflate compression scheme, requires zlib or Apple's libcompression
-    LZFSE,          // an Apple compression scheme, requires Apple's libcompression
-    LZ4,            // lz compression - called "lz4 raw" in libcompression terms, compat with https://code.google.com/p/lz4/
-    LZMA,           // Lempel–Ziv–Markov chain algorithm
+enum class CompressionType {
+  None = 0,    // no compression
+  ZlibDeflate, // zlib's deflate compression scheme, requires zlib or Apple's
+               // libcompression
+  LZFSE,       // an Apple compression scheme, requires Apple's libcompression
+  LZ4, // lz compression - called "lz4 raw" in libcompression terms, compat with
+       // https://code.google.com/p/lz4/
+  LZMA, // Lempel–Ziv–Markov chain algorithm
 };
 
 class ProcessGDBRemote;
 
-class GDBRemoteCommunication : public Communication
-{
+class GDBRemoteCommunication : public Communication {
 public:
-    enum
-    {
-        eBroadcastBitRunPacketSent = kLoUserBroadcastBit,
-        eBroadcastBitGdbReadThreadGotNotify = kLoUserBroadcastBit << 1 // Sent when we received a notify packet.
-    };
+  enum {
+    eBroadcastBitRunPacketSent = kLoUserBroadcastBit,
+    eBroadcastBitGdbReadThreadGotNotify =
+        kLoUserBroadcastBit << 1 // Sent when we received a notify packet.
+  };
+
+  enum class PacketType { Invalid = 0, Standard, Notify };
+
+  enum class PacketResult {
+    Success = 0,        // Success
+    ErrorSendFailed,    // Error sending the packet
+    ErrorSendAck,       // Didn't get an ack back after sending a packet
+    ErrorReplyFailed,   // Error getting the reply
+    ErrorReplyTimeout,  // Timed out waiting for reply
+    ErrorReplyInvalid,  // Got a reply but it wasn't valid for the packet that
+                        // was sent
+    ErrorReplyAck,      // Sending reply ack failed
+    ErrorDisconnected,  // We were disconnected
+    ErrorNoSequenceLock // We couldn't get the sequence lock for a multi-packet
+                        // request
+  };
+
+  // Class to change the timeout for a given scope and restore it to the
+  // original value when the
+  // created ScopedTimeout object got out of scope
+  class ScopedTimeout {
+  public:
+    ScopedTimeout(GDBRemoteCommunication &gdb_comm,
+                  std::chrono::seconds timeout);
+    ~ScopedTimeout();
+
+  private:
+    GDBRemoteCommunication &m_gdb_comm;
+    std::chrono::seconds m_saved_timeout;
+  };
+
+  GDBRemoteCommunication(const char *comm_name, const char *listener_name);
+
+  ~GDBRemoteCommunication() override;
+
+  PacketResult GetAck();
+
+  size_t SendAck();
+
+  size_t SendNack();
+
+  char CalculcateChecksum(llvm::StringRef payload);
+
+  PacketType CheckForPacket(const uint8_t *src, size_t src_len,
+                            StringExtractorGDBRemote &packet);
+
+  bool GetSendAcks() { return m_send_acks; }
+
+  //------------------------------------------------------------------
+  // Set the global packet timeout.
+  //
+  // For clients, this is the timeout that gets used when sending
+  // packets and waiting for responses. For servers, this is used when waiting
+  // for ACKs.
+  //------------------------------------------------------------------
+  std::chrono::seconds SetPacketTimeout(std::chrono::seconds packet_timeout) {
+    const auto old_packet_timeout = m_packet_timeout;
+    m_packet_timeout = packet_timeout;
+    return old_packet_timeout;
+  }
+
+  std::chrono::seconds GetPacketTimeout() const { return m_packet_timeout; }
+
+  //------------------------------------------------------------------
+  // Start a debugserver instance on the current host using the
+  // supplied connection URL.
+  //------------------------------------------------------------------
+  Error StartDebugserverProcess(
+      const char *url,
+      Platform *platform, // If non nullptr, then check with the platform for
+                          // the GDB server binary if it can't be located
+      ProcessLaunchInfo &launch_info, uint16_t *port, const Args *inferior_args,
+      int pass_comm_fd); // Communication file descriptor to pass during
+                         // fork/exec to avoid having to connect/accept
+
+  void DumpHistory(Stream &strm);
 
-    enum class PacketType
-    {
-        Invalid = 0,
-        Standard,
-        Notify
-    };
-
-    enum class PacketResult
-    {
-        Success = 0,        // Success
-        ErrorSendFailed,    // Error sending the packet
-        ErrorSendAck,       // Didn't get an ack back after sending a packet
-        ErrorReplyFailed,   // Error getting the reply
-        ErrorReplyTimeout,  // Timed out waiting for reply
-        ErrorReplyInvalid,  // Got a reply but it wasn't valid for the packet that was sent
-        ErrorReplyAck,      // Sending reply ack failed
-        ErrorDisconnected,  // We were disconnected
-        ErrorNoSequenceLock // We couldn't get the sequence lock for a multi-packet request
+protected:
+  class History {
+  public:
+    enum PacketType {
+      ePacketTypeInvalid = 0,
+      ePacketTypeSend,
+      ePacketTypeRecv
     };
 
-    // Class to change the timeout for a given scope and restore it to the original value when the
-    // created ScopedTimeout object got out of scope
-    class ScopedTimeout
-    {
-    public:
-        ScopedTimeout (GDBRemoteCommunication& gdb_comm, uint32_t timeout);
-        ~ScopedTimeout ();
-
-    private:
-        GDBRemoteCommunication& m_gdb_comm;
-        uint32_t m_saved_timeout;
+    struct Entry {
+      Entry()
+          : packet(), type(ePacketTypeInvalid), bytes_transmitted(0),
+            packet_idx(0), tid(LLDB_INVALID_THREAD_ID) {}
+
+      void Clear() {
+        packet.clear();
+        type = ePacketTypeInvalid;
+        bytes_transmitted = 0;
+        packet_idx = 0;
+        tid = LLDB_INVALID_THREAD_ID;
+      }
+      std::string packet;
+      PacketType type;
+      uint32_t bytes_transmitted;
+      uint32_t packet_idx;
+      lldb::tid_t tid;
     };
 
-    GDBRemoteCommunication(const char *comm_name, 
-                           const char *listener_name);
-
-    ~GDBRemoteCommunication() override;
-
-    PacketResult
-    GetAck ();
-
-    size_t
-    SendAck ();
+    History(uint32_t size);
 
-    size_t
-    SendNack ();
+    ~History();
 
-    char
-    CalculcateChecksum (const char *payload,
-                        size_t payload_length);
+    // For single char packets for ack, nack and /x03
+    void AddPacket(char packet_char, PacketType type,
+                   uint32_t bytes_transmitted);
 
-    bool
-    GetSequenceMutex(Mutex::Locker& locker, const char *failure_message = nullptr);
+    void AddPacket(const std::string &src, uint32_t src_len, PacketType type,
+                   uint32_t bytes_transmitted);
 
-    PacketType
-    CheckForPacket (const uint8_t *src, 
-                    size_t src_len, 
-                    StringExtractorGDBRemote &packet);
+    void Dump(Stream &strm) const;
 
-    bool
-    IsRunning() const
-    {
-        return m_public_is_running.GetValue();
-    }
+    void Dump(Log *log) const;
 
-    bool
-    GetSendAcks ()
-    {
-        return m_send_acks;
-    }
+    bool DidDumpToLog() const { return m_dumped_to_log; }
 
-    //------------------------------------------------------------------
-    // Client and server must implement these pure virtual functions
-    //------------------------------------------------------------------
-    virtual bool
-    GetThreadSuffixSupported () = 0;
-
-    //------------------------------------------------------------------
-    // Set the global packet timeout.
-    //
-    // For clients, this is the timeout that gets used when sending
-    // packets and waiting for responses. For servers, this might not
-    // get used, and if it doesn't this should be moved to the
-    // GDBRemoteCommunicationClient.
-    //------------------------------------------------------------------
-    uint32_t 
-    SetPacketTimeout (uint32_t packet_timeout)
-    {
-        const uint32_t old_packet_timeout = m_packet_timeout;
-        m_packet_timeout = packet_timeout;
-        return old_packet_timeout;
+  protected:
+    uint32_t GetFirstSavedPacketIndex() const {
+      if (m_total_packet_count < m_packets.size())
+        return 0;
+      else
+        return m_curr_idx + 1;
     }
 
-    uint32_t
-    GetPacketTimeoutInMicroSeconds () const
-    {
-        return m_packet_timeout * TimeValue::MicroSecPerSec;
+    uint32_t GetNumPacketsInHistory() const {
+      if (m_total_packet_count < m_packets.size())
+        return m_total_packet_count;
+      else
+        return (uint32_t)m_packets.size();
     }
 
-    //------------------------------------------------------------------
-    // Start a debugserver instance on the current host using the
-    // supplied connection URL.
-    //------------------------------------------------------------------
-    Error
-    StartDebugserverProcess(const char *url,
-                            Platform *platform, // If non nullptr, then check with the platform for the GDB server binary if it can't be located
-                            ProcessLaunchInfo &launch_info,
-                            uint16_t *port,
-                            const Args& inferior_args = Args());
-
-    void
-    DumpHistory(Stream &strm);
-    
-protected:
-    class History
-    {
-    public:
-        enum PacketType
-        {
-            ePacketTypeInvalid = 0,
-            ePacketTypeSend,
-            ePacketTypeRecv
-        };
-
-        struct Entry
-        {
-            Entry() :
-                packet(),
-                type (ePacketTypeInvalid),
-                bytes_transmitted (0),
-                packet_idx (0),
-                tid (LLDB_INVALID_THREAD_ID)
-            {
-            }
-            
-            void
-            Clear ()
-            {
-                packet.clear();
-                type = ePacketTypeInvalid;
-                bytes_transmitted = 0;
-                packet_idx = 0;
-                tid = LLDB_INVALID_THREAD_ID;
-            }
-            std::string packet;
-            PacketType type;
-            uint32_t bytes_transmitted;
-            uint32_t packet_idx;
-            lldb::tid_t tid;
-        };
-
-        History (uint32_t size);
-        
-        ~History ();
-
-        // For single char packets for ack, nack and /x03
-        void
-        AddPacket (char packet_char,
-                   PacketType type,
-                   uint32_t bytes_transmitted);
-
-        void
-        AddPacket (const std::string &src,
-                   uint32_t src_len,
-                   PacketType type,
-                   uint32_t bytes_transmitted);
-        
-        void
-        Dump (Stream &strm) const;
-
-        void
-        Dump (Log *log) const;
-
-        bool
-        DidDumpToLog () const
-        {
-            return m_dumped_to_log;
-        }
-    
-    protected:
-        uint32_t
-        GetFirstSavedPacketIndex () const
-        {
-            if (m_total_packet_count < m_packets.size())
-                return 0;
-            else
-                return m_curr_idx + 1;
-        }
-
-        uint32_t
-        GetNumPacketsInHistory () const
-        {
-            if (m_total_packet_count < m_packets.size())
-                return m_total_packet_count;
-            else
-                return (uint32_t)m_packets.size();
-        }
-
-        uint32_t
-        GetNextIndex()
-        {
-            ++m_total_packet_count;
-            const uint32_t idx = m_curr_idx;
-            m_curr_idx = NormalizeIndex(idx + 1);
-            return idx;
-        }
-
-        uint32_t
-        NormalizeIndex (uint32_t i) const
-        {
-            return i % m_packets.size();
-        }
-
-        std::vector<Entry> m_packets;
-        uint32_t m_curr_idx;
-        uint32_t m_total_packet_count;
-        mutable bool m_dumped_to_log;
-    };
-
-    uint32_t m_packet_timeout;
-    uint32_t m_echo_number;
-    LazyBool m_supports_qEcho;
-#ifdef ENABLE_MUTEX_ERROR_CHECKING
-    TrackingMutex m_sequence_mutex;
-#else
-    Mutex m_sequence_mutex;    // Restrict access to sending/receiving packets to a single thread at a time
-#endif
-    Predicate<bool> m_public_is_running;
-    Predicate<bool> m_private_is_running;
-    History m_history;
-    bool m_send_acks;
-    bool m_is_platform; // Set to true if this class represents a platform,
-                        // false if this class represents a debug session for
-                        // a single process
-    
-    CompressionType m_compression_type;
-
-    PacketResult
-    SendPacket (const char *payload,
-                size_t payload_length);
-
-    PacketResult
-    SendPacketNoLock (const char *payload, 
-                      size_t payload_length);
-
-    PacketResult
-    ReadPacket (StringExtractorGDBRemote &response, uint32_t timeout_usec, bool sync_on_timeout);
-
-    // Pop a packet from the queue in a thread safe manner
-    PacketResult
-    PopPacketFromQueue (StringExtractorGDBRemote &response, uint32_t timeout_usec);
-
-    PacketResult
-    WaitForPacketWithTimeoutMicroSecondsNoLock (StringExtractorGDBRemote &response, 
-                                                uint32_t timeout_usec,
-                                                bool sync_on_timeout);
-
-    bool
-    WaitForNotRunningPrivate (const TimeValue *timeout_ptr);
-
-    bool
-    CompressionIsEnabled ()
-    {
-        return m_compression_type != CompressionType::None;
+    uint32_t GetNextIndex() {
+      ++m_total_packet_count;
+      const uint32_t idx = m_curr_idx;
+      m_curr_idx = NormalizeIndex(idx + 1);
+      return idx;
     }
 
-    // If compression is enabled, decompress the packet in m_bytes and update
-    // m_bytes with the uncompressed version.
-    // Returns 'true' packet was decompressed and m_bytes is the now-decompressed text.
-    // Returns 'false' if unable to decompress or if the checksum was invalid.
-    //
-    // NB: Once the packet has been decompressed, checksum cannot be computed based
-    // on m_bytes.  The checksum was for the compressed packet.
-    bool
-    DecompressPacket ();
-
-    Error
-    StartListenThread (const char *hostname = "127.0.0.1", uint16_t port = 0);
-
-    bool
-    JoinListenThread ();
-
-    static lldb::thread_result_t
-    ListenThread (lldb::thread_arg_t arg);
-
-    // GDB-Remote read thread
-    //  . this thread constantly tries to read from the communication
-    //    class and stores all packets received in a queue.  The usual
-    //    threads read requests simply pop packets off the queue in the
-    //    usual order.
-    //    This setup allows us to intercept and handle async packets, such
-    //    as the notify packet.
-
-    // This method is defined as part of communication.h
-    // when the read thread gets any bytes it will pass them on to this function
-    void AppendBytesToCache(const uint8_t * bytes,
-                            size_t len,
-                            bool broadcast,
-                            lldb::ConnectionStatus status) override;
+    uint32_t NormalizeIndex(uint32_t i) const { return i % m_packets.size(); }
+
+    std::vector<Entry> m_packets;
+    uint32_t m_curr_idx;
+    uint32_t m_total_packet_count;
+    mutable bool m_dumped_to_log;
+  };
+
+  std::chrono::seconds m_packet_timeout;
+  uint32_t m_echo_number;
+  LazyBool m_supports_qEcho;
+  History m_history;
+  bool m_send_acks;
+  bool m_is_platform; // Set to true if this class represents a platform,
+                      // false if this class represents a debug session for
+                      // a single process
+
+  CompressionType m_compression_type;
+
+  PacketResult SendPacketNoLock(llvm::StringRef payload);
+
+  PacketResult ReadPacket(StringExtractorGDBRemote &response,
+                          Timeout<std::micro> timeout, bool sync_on_timeout);
+
+  // Pop a packet from the queue in a thread safe manner
+  PacketResult PopPacketFromQueue(StringExtractorGDBRemote &response,
+                                  Timeout<std::micro> timeout);
+
+  PacketResult WaitForPacketNoLock(StringExtractorGDBRemote &response,
+                                   Timeout<std::micro> timeout,
+                                   bool sync_on_timeout);
+
+  bool CompressionIsEnabled() {
+    return m_compression_type != CompressionType::None;
+  }
+
+  // If compression is enabled, decompress the packet in m_bytes and update
+  // m_bytes with the uncompressed version.
+  // Returns 'true' packet was decompressed and m_bytes is the now-decompressed
+  // text.
+  // Returns 'false' if unable to decompress or if the checksum was invalid.
+  //
+  // NB: Once the packet has been decompressed, checksum cannot be computed
+  // based
+  // on m_bytes.  The checksum was for the compressed packet.
+  bool DecompressPacket();
+
+  Error StartListenThread(const char *hostname = "127.0.0.1",
+                          uint16_t port = 0);
+
+  bool JoinListenThread();
+
+  static lldb::thread_result_t ListenThread(lldb::thread_arg_t arg);
+
+  // GDB-Remote read thread
+  //  . this thread constantly tries to read from the communication
+  //    class and stores all packets received in a queue.  The usual
+  //    threads read requests simply pop packets off the queue in the
+  //    usual order.
+  //    This setup allows us to intercept and handle async packets, such
+  //    as the notify packet.
+
+  // This method is defined as part of communication.h
+  // when the read thread gets any bytes it will pass them on to this function
+  void AppendBytesToCache(const uint8_t *bytes, size_t len, bool broadcast,
+                          lldb::ConnectionStatus status) override;
 
 private:
-    std::queue<StringExtractorGDBRemote> m_packet_queue; // The packet queue
-    lldb_private::Mutex m_packet_queue_mutex;            // Mutex for accessing queue
-    Condition m_condition_queue_not_empty;               // Condition variable to wait for packets
+  std::queue<StringExtractorGDBRemote> m_packet_queue; // The packet queue
+  std::mutex m_packet_queue_mutex; // Mutex for accessing queue
+  std::condition_variable
+      m_condition_queue_not_empty; // Condition variable to wait for packets
 
-    HostThread m_listen_thread;
-    std::string m_listen_url;
+  HostThread m_listen_thread;
+  std::string m_listen_url;
 
-    DISALLOW_COPY_AND_ASSIGN (GDBRemoteCommunication);
+  DISALLOW_COPY_AND_ASSIGN(GDBRemoteCommunication);
 };
 
 } // namespace process_gdb_remote